Which term describes other substances not made by plants (usually include minerals), but are essential for life?

• A. Nutrients
• B. Vitamins
• C. Inorganic
• D. Organic

Answer: (C)

The key idea is how substances essential for life are categorized as organic versus inorganic. Inorganic substances are not built from carbon–hydrogen backbones and are not produced by plants; they include minerals such as calcium, iron, and potassium that organisms need to function. These minerals act as cofactors for enzymes, help maintain fluid and electrolyte balance, and support structural components. Vitamins and other organic nutrients are carbon-based and are typically synthesized by living organisms, including plants, so they don’t fit the clue about not being made by plants. The broad term nutrients spans both organic and inorganic substances, so it isn’t the best fit for highlighting the minerals not produced by plants. Thus, the term described is inorganic.